| Engineering Journal 5.4.3: Configuring IGRP To create the IGRP routing process, you need to perform the tasks described here, starting in global configuration mode. Enable an IGRP routing process by using the command router igrp, which places you in router configuration mode. The full syntax of this command is as follows: router igrp autonomous-system The argument autonomous-system identifies the routes to other IGRP routers, and is used to tag the routing information passed along. When an IGRP routing process is configured, an AS number must be specified. This number may or may not be assigned. The AS number is used to tag updates belonging to one of up to four IGRP routing processes. You use the no router igrp command to shut down the routing process on the AS specified by the autonomous-system argument: no router igrp autonomous-system You associate networks with an IGRP routing process by using the command network. The full syntax of this command is as follows: network network-number The argument network-number is a network number, in dotted-decimal IP notation. Note that this number must not contain subnet information. You can specify multiple network commands. You use the no network command with the network number to remove a network from the list: no network network-number In the following example, a router is configured for IGRP and assigned to AS 109. In the last two lines, two network commands assign the two networks to a list of networks to receive IGRP updates: Router(config)# router igrp 109 network 131.108.0.0 network 192.31.7.0 IGRP sends updates to the interfaces in the specified networks. If an interface's network is not specified, it is not advertised in any IGRP updates.